Why is our 21st birthday so big?

Question

Among all the birthdays, why is the 21st considered such a huge one. Why not the 20th?
Carl, Pimlico

Answer

** Definitive **
Name: Paul, Croydon
Qualification: Over 21
Answer: In medieval times, you had to be 21 before you could own property – it was the age of change. In the USA, there are still quite a few things you can’t do until you are 21. It used to be the same in this country, but it’s no longer the case here.